(1) Field of Invention
This invention relates to integrated circuit (IC) module for packaging IC chips, in particular to ball-grid array IC chips.
(2) Description of the Related Art
In conventional packaging of integrated circuits (IC), protective glue is customarily used to seal the IC module to improve reliability. FIG. 10 shows a typical prior art IC module. An IC chip 50 is mounted on a metal frame with extensions 56 as leads. The IC chip 50 is wire-bonded to the leads 56. The IC chip 50 and the inner portions of the leads 56 are sealed in glue 54. The application of glue requires extra processing step and is therefore not cost effective.
An object of this invention is to eliminate the use of glue in sealing an integrated circuit module. Another object of this invention is to reduce the cost of packaging an IC chip or chips. Still another object of this invention is to eliminate the use of glue in sealing a ball-grid-array IC chip. A further object of this invention is to eliminate the use of glue in sealing a stacked multiple IC chip module.
These objects are achieved by pressure sealing an IC module. The bottom balls of a ball-grid array chip are mated with a first set of pads, which are connected to a second set of pads along the periphery of the package with extended leads for external connection. A frame of insulating material is placed over the second set of pads to seal to package. Alternatively, the IC chip itself may be used to press the leads to the second set of pads. The vacant space between the two sets of pads may be back-filled with insulating material.